Why one of 2015's biggest clothing trends is here to stay

Young people were generally choosing to spend their money on electronics and Starbucks coffee, not apparel.

But that doesn't mean young people completely skipped out on clothes this year. It's obvious they love the dirt cheap Forever 21, and the biggest apparel company in the United States, Nike. In fact, Nike has usurped former teen favorites, Abercrombie & Fitch and Gap.

Interestingly enough, there's a stark polarity between these two teen favorites. One will last a season, if that, and the other is designed to last for years (if washed properly). One is affordable, another is an investment.

This arguably means that young people — who apparently aren't willing to invest in much — are willing to invest in something: their wellness, which isn't a fad...it's a lifestyle.

Think about it: the rise of athleisure has been part of an entire movement, one pegged to boutique fitness classes, a marked focus on eating well, McDonald's introducing a healthier menu, and the — often exhausting and a bit aggressive — #FitSpo trend on Instagram. The increasing uptick in fitness awareness has seemed to replace even Victoria's Secret's usual emphasis on beauty, Megan Garber of The Atlantic pointed out. She noted that rather than zeroing in on the Angel's obvious anomalous figures, the brand focused on how unbelievably fit they were and how much they worked out (and don't forget to buy Victoria's Secret Sport and to "train like an Angel!").

Still, for all its good points, the movement is not without its faults. Although this lifestyle is largely tied to wellness, it's also partially linked to vanity. There's an increasing urgency to look your best when you work out, especially if you go to a swanky boutique class with harshly lit mirrors. People used to think that going to the gym meant a free pass to look like hot roasted garbage. Now, it's the opposite. (Unless you go to Planet Fitness. Then you can be what you want to be, sans judgment.) And the abundant #Fitspo arguably shares many ties to the darker, unsettling, and more obvious hashtag, #Thinspogram.

But athleisure is undoubtedly popular, and it has become a buzzword tossed around with increasing frequency in the apparel industry. As a result, many brands have tried to hop on board with stalwarts Nike, Lululemon, and the on-the-rise Under Armour. Dick's Sporting Goods felt the burn and has tried to venture into the sector. More upscale brands, like Tory Burch, have joined the sportswear brigade, too.

Nike is the top clothing retailer with teens. Nike on Facebook

But the brands that have performed the best and that have seemed to prove they can withstand the emerging competition are the ones that do not sell clothes, but rather, lifestyles — which makes sense, given the movement is about that, and not about trends. Lululemon, Nike, and Under Armour all operate around particular their own particular fitness ethos — community and kumbaya, athleticism, and overcoming obstacles, respectively.

Sure, going to the gym and looking good is cool, but how do you keep the customer from outgrowing your brand? Nike's co-founder Bill Bowerman has said that "if you have a body, you are an athlete," which is incidentally a genius marketing tactic that makes it physically impossible for a customer to outgrow the company. It's arguably the opposite of Forever 21, whose name alone suggests the nightmarish possibility of being permanently trapped in your 21-year-old body, wearing a "going out shirt," Keystone Light in hand, while making poor decisions.

Young people who aren't 21 yet — the mystifying Generation Z— probably like that idea of turning 21 and the sweeping nature of fast fashion; it's romantic to them. But at some point, they might grow out of dispensable fast fashion, and they might start wanting to purchase more durable clothing ( I, personally, have experienced this transition). Fast fashion, ultimately, is fast. It's impermanent. It's attractive. It's a fling. It's sexy. It's disposable. It's your forsaken youth, embodied in a bodycon dress.

Under Armour has become increasingly popular this year. Facebook/Under Armour

Athleisure, on the other hand, is about permanence and endurance. Unlike many trends, your body is one of the few potential constants you can have in your life.

Athleisure also asks you to make better decisions; it pushes to you to make conscious decisions about how you spend your time and money. Don't buy that cocktail, buy a green juice instead. Go to the gym instead of going to happy hour. Go to sleep early instead of staying out allnight. The girl who strictly abides by that script and says all of that out loud ad nauseum is probably cloying, but athleisure asks you to try your best.

Which brings up another reason why athleisure has been so successful and why we likely won't see it getting any less popular come 2016: just like runway fashion, it's aspirational. Athleisure presents a version of ourselves we aspire to be: people who don't miss the gym, people who invest in ourselves, and people who. And in 2016, who doesn't want to at least aspire to be his or her best self?

I know I do. Realistically, I'll probably miss the mark many times, but putting on the stretchy pants for the gym and getting into a healthy lifestyle is at least a start.